Approval by the human studies committee was just received. Recently we have developed new methods for analysis of metabolism in the liver and other organs. The purpose of this study is twofold: 1) to define the distribution of a stable carbon isotope, 13C, in intrahepatic glucose, hepatic vein glucose and peripheral vein glucose, and 2) determine if hepatic gluconeogenesis from a short chain fatty acid, propionate, is increased in patients with noninsulin dependent diabetes after brief fasting. Blood and urine samples will be analyzed by 13C NMR. A total of 16 stable patients (8 controls, 8 with noninsulin dependent diabetes) scheduled for elective cardiac catheterization will be recruited for the study. Prior to the routine catheterization, the hepatic vein will be cannulated from the femoral vein, and patients will be given Tylenol and 13C-labeled propionate by mouth. During the course of the standard catheterization, blood samples will be drawn periodically from the hepatic vein and the femoral vein. All hepatic venous sampling will be completed within 1 hour after the start of the procedure. It is anticipated that this study will establish that simple peripheral venous blood samples provide the same carbon isotope data as more invasive (hepatic vein) sampling. This study will also test whether fasting gluconeogenesis is increased in patients with noninsulin dependent diabetes.